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A146535 Numerator of (2*n-1)/3. 9
1, 1, 5, 7, 3, 11, 13, 5, 17, 19, 7, 23, 25, 9, 29, 31, 11, 35, 37, 13, 41, 43, 15, 47, 49, 17, 53, 55, 19, 59, 61, 21, 65, 67, 23, 71, 73, 25, 77, 79, 27, 83, 85, 29, 89, 91, 31, 95, 97, 33, 101, 103, 35, 107, 109, 37, 113, 115, 39, 119, 121, 41, 125, 127, 43, 131, 133, 45 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

From Jaroslav Krizek, May 28 2010: (Start)

a(n+1) = numerators of antiharmonic mean of the first n positive integers for n >= 1.

See A169609(n-1) - denominators of antiharmonic mean of the first n positive integers for n >= 1. (End)

LINKS

Table of n, a(n) for n=1..68.

Index entries for linear recurrences with constant coefficients, signature (0,0,2,0,0,-1).

FORMULA

From R. J. Mathar, Nov 21 2008: (Start)

a(n) = 2*a(n-3) - a(n-6).

G.f.: x(1+x)(1+5x^2+x^4)/((1-x)^2*(1+x+x^2)^2). (End)

MATHEMATICA

Table[Numerator[(2 n - 1)/6], {n, 1, 100}]

LinearRecurrence[{0, 0, 2, 0, 0, -1}, {1, 1, 5, 7, 3, 11}, 100] (* Harvey P. Dale, Feb 24 2015 *)

PROG

(PARI) a(n) = numerator((2*n-1)/3); \\ Altug Alkan, Apr 13 2018

CROSSREFS

Cf. A146306, A146307, A146308, A146309, A146310, A146311, A146312, A146313

Trisections: A016921, A005408, A016969. [R. J. Mathar, Nov 21 2008]

Sequence in context: A144543 A205135 A076567 * A141650 A058091 A258162

Adjacent sequences:  A146532 A146533 A146534 * A146536 A146537 A146538

KEYWORD

nonn,easy,frac

AUTHOR

Artur Jasinski, Oct 31 2008

EXTENSIONS

Name edited by Altug Alkan, Apr 13 2018

STATUS

approved

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Last modified March 19 15:02 EDT 2019. Contains 321330 sequences. (Running on oeis4.)